Composition of matter and use thereof in joint sealing



United States Patent [72] Inventors Peter M. Berry Longueuil, Quebec,Canada; John Joe Kavalir, Two Mountains, Quebec, Canada [21] App1.No.657,230

[22] Filed July 31,1967

[45] Patented Aug. 11, 1970 [73] Assignee Uniroyal Inc.

' New York, New York a Corp. of New Jersey [32] Priority April 24, 1967[3 3] Canada [54] COMPOSITION OF MATTER AND USE THEREOF IN JOINT SEALING6 Claims, 2 Drawing Figs.

[52] U.S.Cl 94/18, 260/876 [51] Int. Cl ..E01c 11/10, C08f 15/00 [50]Field of Search 260/876, 2.3, 5; 94/18 Primary Examiner Jacob L.Nackenoff Att0rney Patrick Bright ABSTRACT: There is disclosed a newcomposition of matter comprising a thermoplastic block copolymer ofbutadiene and styrene and reclaimed rubber and use thereof particularlyfor joint sealing purposes. This composition is extruded into a stripused to seal joints. In a preferred embodiment the extrusion is a hollowstrip with flat sidewalls and slotted bottom, a special rubber cement asa primer is applied to the flat sidewalls of the strip and to the wallsof the joint in the pavement or the like, whereupon the strip isinserted in the joint, the walls of the strip are allowed to springoutwardly into contact with the walls of the joint, and the solvent inthe primer is then allowed to evaporate. Thus the uncured strip iscemented tightly in place.

COMPOSITION OF MATTER AND USE THEREOF IN JOINT SEALING This inventionrelates to a new expansion joint composition, an expansion joint stripof novel design made therefrom, a method of sealing an expansion jointwith such a strip and the resulting concrete paving assembly.

For many years strenuous efforts have been made to develop asatisfactory technique for sealing expansion joints in concretehighways, airport runways, and the like, in order to prevent the accessof water and salt into the joint with resulting damage due to freezingof water and'undesired chemical action of salt on the concrete in thejoint area. So far as we are aware all previous proposals have beensubject to various serious drawbacks.

It has recently been proposed to use a cured neoprene extrusion ofcomplex multi-channel cross-section as an expansion joint sealant strip.According to this proposal, a cured extruded neoprene strip havingnarrow walls extending in crisscross fashion from one side wallto theother side wall is inserted in the joint so as to be under compression.Typically the strip is compressed from 50 to 75% prior to its insertion.With this system there is very low adhesion of the strip to the walls ofthe joint. Because the strip is used only in compression and is notpermanently adhered to the sides of the joint, relative up and downmovement of the adjoining concrete slabs as traffic passes over thejoints gradually causes the strips to work loose so'that they projectabove the pavement and soon are pushed out altogether. The'loose stripsare a serious traffic hazard. This propensity of the strips to come outof the joints has ruled out altogether the use. of this system onairport runways because of the danger that the strips will be suckedinto jet engines. Also the strips are expensive and difficult to apply.

Our invention involves a novel approach to the expansion joint'problem.In our system the walls of an uncured strip are permanently bonded tothe walls of the joint so that the joint is completely sealed againstaccess of water, salt, etc. The strip is so designed that in combinationwith this permanent bonding feature it can expand or contract freelywith the contraction and expansion of the concrete slabs withoutreducing or interfering with the integrity of the seal. The permanentstrong bonding feature is made possible by making the strip from aspecial uncured composition which we have. invented and which is fullydescribed below.

In the accompanying drawing, FIG. 1 is a cross-section of an expansionjoint strip made according to our invention, prior to its insertion inthe joint, and FIG. 2 is a cross-section of the finished joint assembly.7

In practicing our invention we first prepare a mixture of (l) athermoplastic polymer selected from the group consisting of a blockcopolymer having the general configuration A-B-A wherein the As arepolymeric blocks of alkenyl aromatic hydrocarbons typified by styrene,each A having an average molecular weight of 2,500 to 100,000 and B is apolymeric block of a conjugated diene, typified by butadiene, having anaverage molecular weight of 25,000 to 500,000 and -hydrogenatedderivatives of such block copolymers and (2) reclaimed rubber. The blockcopolymer, whether hydrogenated or not, is fully described in CanadianPatent 740,027 which is hereby incorporated herein by reference. Anykind of reclaimed rubber may be used, examples being neoprene reclaim,SBR reclaim including high styrene SBR 7 (made with an unusually highstyrene-butadiene ratio or by blending regular SBR with a highstyrene-low butadiene resinous copolymer) reclaim, butyl reclaim,natural rubber reclaim, butadiene-acrylonitrile rubber reclaim, EPDM reclaim, etc. Instead of using a single kind of reclaim we can use aplurality of types of reclaim.

The reclaimed rubber component of our composition is the rubbercompounding material commonly and widely available under the designationreclaimed rubber" or rubber reclaim" and as is well-known made byreclaiming vulcanized natural or synthetic rubber, especially that inscrap form, by methods which are equally'well-known to the art.Examples-of Introduction to Rubber Technology, edited by Morton,

published by Reinhold, 1959.

Reclaimed Rubber by Ball, published by Rubber Reclaimers Association,Inc., New York,-l947.

Synthetic Rubber, edited by Whitby, published by Wiley,

1954, Chapter 17.

India Rubber World, articles on pages 772-774 of September, 1953 issueand pages 63-67 of October, 1953 issue.

The relative proportions of the block copolymer and reclaimed rubber canbe varied widely depending upon the properties, including physicalproperties, desired in the joint sealing material. Preferably we usefrom 50 to 200 parts by weight of rubber reclaim per parts of blockcopolymer.

In order to facilitate extrusion of the block copolymerreclaimcomposition into the desired strip and to confer on the strip thedesired physical properties, particularly at low temperatures which maybe as low as 40F., we prefer to incorporate substantial proportions ofan extrusion aid or aids and one or more compatible plasticizers,typically employing from 5 to 45 parts of extrusion aid and 25 to 100parts of plasticizer with 100 parts of the block copolymer and from 50to 200 parts of rubber reclaim, all parts being by weight.

The preferred extrusion aid is mineral rubber which, as is well-known inthe art, is a bituminous material, typified by gilsonite or blownpetroleum asphalt and described for example on pages 749 and 750 of TheChemistry and Technology of Rubber" by Davis and Blake, (published 1937by Reinhold) and on page 157 of Modern Rubber Chemistry (published 1948by Van Nostrand) by Barron.

Other extruding aids known to the art may be used in place of or inaddition to mineral rubber. One such extruding aid which gives excellentresults when used in relatively small amounts in conjunction withmineral rubber, is a fatty acid soap.

As the plasticizer component we may use any non-volatile plasticizer orplasticizers compatible with the other components of the mixture andtypified by monomeric esters such as tricresyl phosphate, dioctylphthalate, etc., plasticizing resins for example a plasticizing resinderived from urea-formaldehyde and exemplified by Plastigen G made byBASF, a plasticizing polyester or alkyd resin, often termed a polymericester plasticizer, exemplified by the resinous polyester materials soldunder the trademark Paraplex" made by Rohm & Haas, etc., or non-volatilepetroleum oils commonly used as extender oils for rubbery materials,exemplified by Circosol 4240/42 x H and Circolight oils both made by SunOil Co. As already indicated, we may use several plasticizers instead ofonly one.

For certain installations, where black expansion joint seals are notdesired, we may make light-colored or even pastelcolored strips byappropriate selection of the components. The most important factors indetermining the color of the extruded strip are the colors of thereclaim, extrusion aid and plasticizers. If desired, pigments other thanthe pigment supplied by the reclaim can be included for particular coloreffects, for example where expansion joints in colored concrete are tobe filled.

The several components of the composition of our invention areintimately mixed together in any suitable way wellknown in the rubberart, to achieve a good mixture. This mixture is then extruded intheconventional manner used in rubber technology using an extrusion dieshaped to give the supplied in reels from which it can simply andrapidly be fed into the joint, using suitable applicator equipment forapplying the primer describedbelow to the walls of the joint and to theStrip.

; Typieally t'he" eIon'gat-ion'of the materialof'our strip ranges from500 to 1000% over a temperature range of from -40?F. to +120F.; thisrange embraces the temperatures commonly encountered in this country.Its resiliency and hardness are such as to prevent the undesiredpenetration of stones, gravel, etc. into the joint, which would destroyits effectiveness, and yet the hardness is not so great at sub-zerotemperatures such as 40F. as to make the strip brittle. With regard toelasticity, the material returns, after elongation to 200%, almostimmediately to its original length and after elongation to 1000% returnsto 150% of its original length within 1 minute and to its originallength within minutes.

Referring to FIG. 1, the extruded strip comprises downwardly andoutwardly extending side walls 2, a troughlike upper wall constituting ahinge formed by portions 3 which slope downwardly and mergeat the center4 in such a way that when the strip I is compressed laterally forinsertion it will not bulge upwardly, and integral downwardly andinwardly extending projections 5 which terminate short of the center soas to allow compression of the strip just prior to insertion in thejoint. These projecting portions 5 are pointed as indicated at 6 tofacilitate insertion. The outer walls 7 of projections 5 are sloped sothat the projections together have a pointed configuration whichfacilitates such insertion.

The design of strip 1 as extruded is such that when the depending sidemembers formed by side walls 2 and projections 5 are pushed towards oneanother to the point where the outer faces 8 of walls 2 aresubstantially parallel to each other, the distance between faces 8 isonly very slightly wider than the width of the joint to be filled. Thusthe extrusion is predesigned to fit a joint of a particular width. Thedesign of the extrusion l portrayed in FIG. l is such that there is ahinging action of the depending side members. In other words, portions 3constitute a hinge and the characteristics of the material from whichthe extrusion is made are inherently such that when the dependingportions are pushed inwardly towards one another and then released theyresume, so far as they can, the original position they had in theextrusion as it was formed. These featuresare extremely important inachieving the results of our invention.

Now referring particularly to FIG. 2, in sealing a joint in accordancewith our invention, we first coat the upper portion of the walls- 9 ofthe adjacent concrete slabs 10 with a layer 11 of a primer which is aneoprene cement (i.e. an organic solvent solution of neoprene containinga curative or curatives) capable of forming in cooperation with thematerial of the extrusion an adhesive bond which permanently andstrongly bonds the walls 2 of the strip 1 to the concrete and forming afluidtight seal therebetween. This primer also penetrates the permeablewalls of the concrete slabs thereby strengthening the concrete and, moreimportantly, preventing accidental in- Toluol H:

filtration of water or salt solution into the concrete next to the jointand into the joint area itself. The faces 8 of strip I are also coatedwith this primer cement just prior to insertion of the strip. The stripis then inserted into the joint and properly positioned as by means of aprofiled roller. The solvent from the primer immediately starts todissolve the material constituting the strip. After insertion the stripexpands so as to position its side walls against the concrete. Rapidevaporation of the organic solvents in the primer takes place throughthe pores ofthe adjoining concrete. The result is that within 1/2 to Ihour, depending on atmospheric conditions and the solvents used, aperfect physical bond between the walls of the strip and the concrete isachieved and the pavement can be opened to traffic. Because of curing ofthe neoprene in the primer, which starts immediately upon evaporation ofthe organic solvents, maximum adhesion between strip and concrete isobtained within 2 to 3 days after insertion.

While our invention is usually applied to expansion joints formedbetween slabs of concrete it can also be applied in exactly the same wayalready described to expansion joints formed between a concrete slab anda rigid steel member or between two rigid steel members, such as areoften encountered in bridges.

A typical primer formulation suitable for use in our invention is aso-called rubber cement made from neoprene compounded with suitablecuratives, such as magnesium oxide or zinc oxide or both, an antioxidantif desired and a phenolic resin or resins ofthe type commonly used inmaking neoprene 3O cements, all dissolved and suspended in a suitablevolatile organic solvent or solvents also of known type to give anappropriate total solids content. One such formulation which we havefound to give outstanding results is as follows:

Parts by weight Neoprene AF (so-called self-curing neoprene) 100Magnesium oxide (curative for neoprene) 4 Zine oxide (curative forneoprene) 5 Antioxidant a 1 Heat-reactive oil-soluble tertiary butylpheital-formaldehyde resin (such as TR-14634 made by Union Carbide) 45Thermoplastic Terpene-modilicd phenol formaldehyde resin, typicallyhaving a capillary melting point of about 335 F.

(such as Dnrcz 12603 made by Hooker Chemical) Ethyl acetate.

1 To a total solids content of 22%.

EXAMPLES 1 TO 7 Neoprene reel S13 R reclaim.

Butyl reclaim High-styrene SBR reelaim High-styrene SBR reelain1..Natural rubber reclaim.

Mineral rubber 2 10.00 10. 00 10.00 10.00 Tricresyl ph0sphate 15. 00 15.00 15. 00 15.00 llastigelt (3-50 3 .t 15.00 15. 00 10.00 10.00 Nu-Slip(Fatty acid soap) 2.00 2.00 2.00 2.00 2.00 2.00 2.00

Typicallhysieal Properties at RIP. (76 F.)

Tensile 1, 280 1,855 1, 240 1, 140 1, 480 1,285 I, 210 Elongation,percent 865 045 .835 700 ,840 880 850 Modulus:

210 2'20 190 220 215 150 200%. 255 285 245 205 285 180 v 300 o 205 355.305 315 335 240 100 I Shore "A" hardness 57 55 54 55 -56 .54 57- 1 Astyrene-butadieue block copolymer of the type shown in Canadian Patent740,027.

product.

It will be understood that the views of the drawing are greatly enlargedsince the width of expansion joints generally ranges from 1/4 inch to 1inch.

From the foregoing description it will be seen that we have invented anovel system for sealing expansion joints in concrete pavement, whichsystem is perfectly adapted for use in highways, airport runways and thelike and gives many advantages over previously proposed systems. Theseveral features of our invention cooperate in a new way to achievethese new results. The essential features which provide these resultsare the composition of the expansion joint material itself, the designof the extrusion and the primer system. The fact that the joint materialis uncured is a key factor in our system because it enables therequisite permanently strong adhesive bond between it and the walls ofthe joint to be achieved. Ifa cured material were used for the strip itwould not be possible to develop the requisite permanently strongadhesive bond which is at the heart of our invention. Another importantfeature of our invention is that the extrusion strip material isresilient so that after being laterally compressed for insertion intothe joint and then released the depending side portions of the stripimmediately spring outwardly and contact the joint walls with sufficientforce to hold the strip in place until the strong adhesive bond isestablished.

It will be understood that this description of our invention isillustrative and that numerous modifications thereof can be made withoutdeparting from the spirit of our invention.

OTHER USES OF OUR COMPOSITION pansion joints in so-called parapets whichare vertical walls at the edges of highways and the like. We can alsouse our composition, typically in the form of an extrusion of suitablecross section, anywhere in construction where it is desired to sealagainst the entrance of water or outside air or against the leakage ofwater or air. Thus, we can use it for sealing against the leakage of hotor cold conditioned air from the interior of a building to theatmosphere. We can use our technique in socalled curtain wall buildingconstruction for sealing the joints between adjacent exterior verticalwall panels. We can use it for sealing the joints around doorways,windows, etc. In curtain wall applications, we generally prefer to usean extrusion much like that shown in FIG. 1 except that the outer (i.e.,upper as viewed in that figure) face is completely flat, instead oftrough-like, in order that when the extrusion is installed in the jointthe outer face of the extrusion will be flush with the panels and give apleasing appearance. The color of the extrusion and the primer used tobond it in place will of course be adjusted so as to match the color ofthe surrounding structure.

Our composition can also be used for sealing the joints between doors,windows and other elements of a buiding and the structure of thebuilding proper. Thus, it can be used, preferably in the form of atriangular extrusion, for corner joints such as are encountered aroundthe frames of doors and windows, the primer being applied over the areawhich must be sealed in order to hold the extrusion in position. It canalso be used for sealing glass in a window frame; in this application itmay be extruded in the form of a channel which is slipped over the edgesof the glass prior to positioning in the frame, the glass beingsubsequently locked in place in any obvious way. Our composition canalso be used as a weather stripping material; in this usage thecomposition is typically applied as an extrusion of varying design suchthat one side is adhered to a rigid member and another portion of theextrusion is hingelike and is compressed by the closing of the door orwindow in order to provide the necessary seal.

Our composition is also well adapted to be used in sheet form, typicallycalendered, for flashing and roofing. For flashing or roofingapplications we apply a suitable organic solvent, such as for exampletoluol or xylol, which can be used either by itself or in the form of arubber cement, to the roofing substructure in order to effect permanentbonding of the flashing or roofing. In roofing applications we typicallyplace large sheets of our composition in position with slightoverlapping at the edges and we effect fusion of the material in theoverlapping area to form an integral joint by the application of anorganic solvent or rubber cement of the type just referred to; suchfusion of the material in the overlapping areas is possible because ourcomposition is uncured.

Our composition can also be used in sheet form for holding water inirrigation ditches or basins or in the reservoirs behind dams. In thisapplication large sheets of the material are disposed in slightlyoverlapping fashion over the earth area and the overlapping portions ofthe sheets are fused in the manner just described. In this applicationfor greater strength and tear resistance we often prefer to admixreinforcing fibrous material with our composition at the time of itspreparation. Any suitable fibrous material may be employed for thispurpose, examples being sisal, cotton fiber, nylon fiber, ground uncuredrubberized textile fabric cuttings which are formed as waste in themanufacture of pneumatic tires, etc.

Accordingly it will be seen that the composition of our invention has agreat many useful applications. It will be understood of course that theforegoing is by no means a complete enumeration of the uses to which ourcomposition may be put.

We claim:

1. A composition of matter comprising the following components:

(1) a polymer of the group consisting of a block copolymer having thegeneral configuration A-B-A wherein the As are polymeric blocks ofalkenyl aromatic hydrocarbons, each A having an average molecular weightof 2,500 to 100,000 and B is a polymeric block ofa conjugated dienehaving an average molecular weight of 25,000 to 500,000 and hydrogenatedderivatives thereof,

(2) reclaimed rubber made by devulcanizing cured diene rubbers,

(3) an extrusion aid selected from the group consisting of mineralrubber, fatty acid soap, and mixtures thereof, and

(4) plasticizer selected from the group consisting of monomeric esters,plasticizing resins, non-volatile rubber extender oils, and mixturesthereof in relative proportions by weight of from 50 to 200 parts ofreclaimed rubber, from 5 to 45 parts of extrusion aid, and from 25 toparts of plasticizer per 100 parts of said polymer.

2. A joint sealing strip comprising an uncured extrusion of acomposition of matter comprising the following components:

(1) a polymer of the group consisting of a block copolymer having thegeneral configuration A-B-A wherein the As are polymeric blocks ofalkenyl aromatic hydrocarbons, each A having an average molecular weightof 2,500 to 100,000 and B is a polymeric block ofa conjugated dienehaving an average molecular weight of 25,000 to 500,000 and hydrogenatedderivatives thereof, and

(2) reclaimed rubber made by devulcanizing cured diene rubbers, inrelative proportions by weight of from 50 to 200 parts of reclaimedrubber per 100 parts of said polymer.

3. A joint sealing strip comprising an uncured extrusion of a comprisingthe following components:

(1) a polymer of the group consisting of a block copolymer having thegeneral configuration A-B'A wherein the As are polymeric blocks ofalkenyl aromatic hydrocarbons, each A having an average molecular weightof 2,500 to 100,000 and B is a polymeric block of a conjugated dienehaving an average molecular weight of 25,000 to 500,000 and hydrogenatedderivatives thereof,

(2) reclaimed rubber made by devulcanizing cured diene rubbers,

(3) an extrusion aid selected from the group consisting of mineralrubber, fatty acid soap, and mixtures thereof,

and 200 parts of reclaimed rubber per 100 parts of said (4) plasticizerselected from the group consisting of polymers, said extrusion prior toplacement having monomeric esters, plasticizing resins, non-volatiledownwardly and outwardly extending side walls, an inrubber extender oilsand mixtures thereof in relative tegral trough-like upper wall, andhaving its lowerporproportions by weight of from 50 to 200 parts of tionformed by integral downwardly and inwardly exreclaimed rubber, from 5 to45 parts of extrusion aid, tending pointed projections terminating shortof the and from 25 to 100 parts of plasticizer per 100 parts of center,said extrusion prior to placement being slightly said polymer. widerthan the joint and having its side walls coated 4. An expansion jointsealing strip comprising an uncured with said primer, allowing saidstrip to expand outextrusion of a composition comprising wardly in thejoint so that said side walls press against (1) a polymer of the groupconsisting of a block the primed walls of the concrete slabs in parallelrelacopolymer having the general configuration A-B-A tionship to saidprimed walls with said projections terwherein the A's are polymer blocksof alkenyl aromatic minating short of the center of the joint, andallowing hydrocarbons, each A having an average molecular the solvent inthe primer to diffuse and the primer to set weight of 2,500 to 100,000and B is a polymeric bl k and permanently and strongly bond said sidewalls to of a conjugated diene having an average molecular h all f h jntweight of 25,000 to 500,000 and hydrogenated derivatives thereof, and

(2) reclaimed rubber made by devulcanizing cured diene rubbers inrelative proportions by weight of from 50 to 6. A concrete pavementcomprising adjacent concrete slabs having spaced walls forming anexpansion joint, and disposed in said joint an uncured extrusion of acomposition comprising the following components:

(1) a polymer of the group consisting of a block weight of 25,000 to500,000 and hydrogenated derivatives thereof, and

(2) reclaimed rubber made by devulcanizing cured diene rubbers inrelative proportions by weight of from 50 to 200 parts of reclaimedrubber per 100 parts of said polymer, said extrusion having downwardlyand outwardly extending side walls, an integral trough-like upper walland having its lower portion formed by integral downwardly and inwardlyextending pointed copolymer having the general configuration A-B-Awherein the As are polymeric blocks of alkenyl aromatic hydrocarbons,each A having an average molecular weight of 2,500 to 100,000 and B is apolymeric projections terminating short of the enter, block of aconjugated diene having an average molecu- 5. The method of sealing anexpansion joint in a concrete Weight Of 25,000 to 500,000 and hy r g napavement which comprises coating the adjacent walls of the derivativesthereof, and concrete slabs forming the joint with a primer comprising a(2) recla'med rubber made y devulcanilzmg cured dene neoprene cement,placing in the joint an uncured extrusion of rubbers m mauve propomollsby we'ght from Q a composition comprising the following components:parts per pans of 52nd pojymerr extrusion (1) a polymer of the groupconsisting of a block having a trough-like upper wall, Integral parallelside copolymer having the general configuration walls permanently andstrongly bonded to the walls of wherein the A's are polymeric blocks ofalkenyl arothe y a Pnmer and havmg lower P matic hydrocarbons, each Ahaving an average molecufol-med by 'P f downwarifly and mwardly extendmglar weight of 2,500 to 100,000 and B is a polymeric 40 pointed proections terminating short ofthe center. block of conjugated diene havingan average molecular

